Hundreds Of Products Ready Today. Dispatch/Collection Do Sparco Seat Runners Bolt Straight To The Car? Fitting R100s To An MX-5 NB
A customer asked us this week whether Sparco’s sliding runners bolt straight to the car, or whether he needed brackets as well. He has an NB Miata and he is buying a pair of R100s. It is a fair question and the answer catches a lot of people out, because the runners look exactly like the part that would bolt to the floor.
They do not. The runners are the piece that goes between the seat and a mount, and they are not car specific at all. Sparco’s own kit says so: it bolts to the underside of a base mount seat and lets the seat slide on the sub-frame beneath it. So for an NB you need three things, and the middle one is the piece that actually knows what car you own.
- The R100 is a base mount seat on Sparco's 345mm x 271mm pattern, shared with OMP and Corbeau
- Sparco's runner kit is not vehicle specific, it fits any seat on that pattern
- The NB specific part is the bracket underneath, and there are two routes for a Miata
- One Planted bracket for the NB is a side mount despite the name, so it will not take an R100
The three parts, in order
Working from the floor up, a seat conversion is a sub-frame or bracket, then runners, then the seat. Miss the middle one and nothing bolts to anything.
The bracket
Bolts to the car's own floor mounting points. This is the only vehicle specific part, and it is the one you have to get right for an NB. It sets your final seat height too.
The runners
Sit between bracket and seat and give you fore and aft adjustment. Sparco's kit carries the 345mm x 271mm pattern and is not car specific, so it works under any seat on that pattern.
The seat
The R100, sold as seat only. Base mount, 345mm x 271mm, 4 point harness compatible, and narrow enough in the body to suit a small cockpit like the Miata's.
Two ways to do it on an NB
The Miata is well served here, and the two routes are a long way apart on price, so it is worth knowing both before you order.
Jass adapter rails, the direct route
Jass Performance make adapter rails for the Mk1 and Mk2 MX-5 listed specifically against the Sparco R100 and Sprint. At £42.00 inc VAT a side they are far and away the cheapest way in. Worth a call to confirm how they mount on your car before ordering.
Planted bracket and Sparco runners
The full aftermarket route. The Planted NB bracket is a flat plate that bolts to the floor and takes the seat and runner assembly on top, at £222.60 inc VAT a side, with the Sparco runner kit at £78.00 for the pair.
-
From £35.00 Excl. VAT Select options This product has multiple variants. The options may be chosen on the product page
-
From £235.00 Excl. VAT Select options This product has multiple variants. The options may be chosen on the product page
The bracket that looks right and is not
Planted list two brackets for the NB and the names read like a height choice. They are not. One is a flat plate that a seat and runners bolt down onto, which is what you want under an R100. The other is a pair of vertical uprights, which is a side mount, and a reclining seat on runners will not go on it at all. We got caught by the same pair on the NA chassis, so it is worth showing them side by side.
What it costs both ways
| Part | Route A, Jass rails | Route B, Planted and runners |
|---|---|---|
| Seat, R100 single | £282.00 | £282.00 |
| Vehicle specific mount | £42.00 a side | £222.60 a side |
| Runners | Ask us, see below | £78.00 the pair |
| One seat, driver only | From £324.00 | From £543.60 |
| Pair of R100s | £540.00 for the two seats | £540.00 for the two seats |
Prices include VAT and were correct on 14 August 2026. The R100 is £282.00 as a single and the black and blue pair comes in at £540.00, so buying both sides together saves £24.00. Both Planted brackets and the Jass rails are priced per side, so a pair of seats needs two of whichever you choose.
![Planted Technology Mazda MX-5 Miata [NB Chassis] (1998-2005) LOW Seat Bracket](https://www.sportseats4u.co.uk/wp-content/uploads/sites/2/2026/08/SB255PA-2-300x300.jpg)
Common questions
So the runners definitely do not bolt to the floor?
Correct. Sparco's runner kit bolts to the underside of the seat and slides on the sub-frame below it, and it is not car specific. There is nothing in the kit that knows what an MX-5 floor looks like. The bracket underneath is the part that does.
Will the Sparco runners fit anything other than a Sparco seat?
Yes. They carry the 345mm x 271mm pattern, which Sparco, OMP and Corbeau base mount seats all share. Whatever the listing says about brand, the pattern is what decides it. Side mount bucket seats do not use runners at all.
Do I need runners at all?
Only if you want to move the seat. Some people building a track car bolt the seat down solid and set it once, which saves weight and a little height. If the car is driven by more than one person, or on the road, you will want the adjustment.
Which is better on an NB, the cheap route or the Planted one?
They do different jobs. The Jass rails are the quick, inexpensive way to get an R100 into the car. The Planted plate is a full replacement bracket and gives you a known, engineered seat position, which matters more if you are chasing a low driving position or fitting a harness and a bar. Tell us which of those you are after and we will point you at the right one.
Anything to watch on an NB specifically?
Headroom, if the roof goes up. The Miata cockpit is tight and a seat sitting even slightly higher than standard is noticeable. That is the main reason people ask about the low bracket, and the main reason it is worth telling us your height when you order.
What we would order
For a road driven NB getting a pair of R100s, we would start with the Jass adapter rails, because £42.00 a side against £222.60 is a big difference for a car that is not chasing a competition seat position, and the rails are listed against the R100 by name. If the car is going on track, or you want the seat as low and as fixed as you can get it, the Planted plate with the Sparco runner kit is the better piece of engineering and worth the money.
Either way, order the seat, the mount and the runners together. If you tell us your height and whether the roof is up or down most of the time, Cameron will check the combination before it goes out. Ring us on 0115 9893488 and we will get it right first time.